Open Source Windows

Some days you just have to shake your head and wonder. As it turns out, I'm a little late to hear about this, but nonetheless, I'm still shaking my head.

It turns out that Windows has gone open source. And (!!) it's not being made by Microsoft anymore. Well, Windows™ is still made by Microsoft. Windows is now made by a group under the gise of ReactOS.
ReactOS® is a free, modern operating system based on the design of Windows® XP/2003. Written completely from scratch, it aims to follow the Windows® architecture designed by Microsoft from the hardware level right through to the application level. This is not a Linux based system, and shares none of the unix architecture.
So essentially, these people are taking the Windows architecture (based on XP/2003), and redesigning it from scratch. Or rather, are re-coding it from scratch, because redesigning would imply making something different. Sounds vaguely familiar to, oh, something called Vista. Except uglier.

Now, that nagging feeling we are all getting right about now should be visualized as a pack of rabid lawyers. Isn't this considered copyright infringement? They outright define the product as a copy.

And what about the end users? Are all programs designed to run on Windows supposed to be able to run on this ReactOS? Why bother with testing? The XP architecture is now almost 8 years old by now. That means anything designed to run on Vista, or soon to be designed to run on Windows 7, wouldn't stand a snowballs chance in hell, running on ReactOS.

I would love to see how a .NET application runs on it.